I'm trying to send an e-mail from a module I'm writing, but I keep getting this error message, even when I hardcode a valid address in the call to drupal_mail():
Warning: mail() [function.mail]: SMTP server response: 550 The address is not valid in DefaultMailSystem->mail() (line 77 of C:\Program Files (x86)\wamp\www\drupal-7.0\modules\system\system.mail.inc).
How do I fix this?